The present invention relates to a process for polymerizing addition polymerizable monomers, such as ethylene or propylene, or combinations of one or more olefin monomers such as combinations of ethylene with one or more C.sub.3-8 .alpha.-olefins, and optionally one or more copolymerizable dienes to produce polymers having a high degree of long chain branching (LCB) using a catalyst composition comprising a Group 3-10 metal complex and a silane or hydrocarbylsilane branching agent. The resulting polymers may be usefully employed in the preparation of solid objects and articles such as a moldings, films, sheets and foamed objects by molding, casting or the like process.
In WO 97/42234 there is disclosed a process for the preparation of polymers of vinylidene aromatic monomers having a stereoregular structure of high syndiotacticity, by the use of Group 4 metal coordination catalysts and a hydrocarbylsilane or dihydrocarbylsilane adjuvant. In Journal of the American Chemical Society, 1995, 117, 10747-19748, the use of silanes as chain transfer agents in metallocene-mediated olefin polymerizations was described. The products formed included silyl terminated polyolefins.
In U.S. Pat. Nos. 5,272,236, 5,278,272, 5,525,695 there are disclosed certain ethylene homopolymers and ethylene/ .alpha.-olefin copolymers having a LCB of at least 3 chains per 10,000 carbons and a process for their preparation wherein the reincorporation of in situ generated vinyl terminated oligomers or polymers into the growing polymer chain, especially by means of a continuous polymerization process is disclosed. Although such process is relatively efficient for preparing ethylene homopolymers and copolymers, it is not particularly efficient or possible for use for forming long chain branches in homopolymers of C.sub.3-8 .alpha.-olefins, or copolymers of mixtures of C.sub.3-8 .alpha.-olefins. In U.S. Pat. No. 5,665,800 the above process was utilized to prepare EPDM compolymers having melt flow ratio, I10/I2 greater than 5.63, a molecular weight distribution, Mw/Mn, defined by the equation: Mw/Mn &lt;(I10/I2)-4.63, and a critical shear stress at onset of gross melt fracture of greater than about 4.times.10.sup.6 dynes/cm.sup.2. Generally increased long chain branching content is desired in olefin polymers due to improved melt rhelogy of the resulting polymer.
In U.S. Pat. No. 5,444,145, copolymers of ethylene and a branched olefin monomer are disclosed. Disadvantageously, the preparation of such copolymers by the use of the foregoing technique requires the use of a relatively expensive olefin, containing the desired preformed branched structure. Such a process is relatively inflexible and unsuited for commercial use. A process for forming long chain branched .alpha.-olefin copolymer products which may utilize normal, e.g. unbranched olefin monomers is still desired in the industry. For the teachings contained therein, the foregoing patents, publications and equivalent United States patent applications are hereby incorporated by reference.